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(November 24, 2009 - Insidermedicine) Dr. Sanjay Sharma, MD, MSc, FRCSC, a Retina Specialist from Hotel Dieu Hospital and Professor of Ophthalmology at Queen's University, discusses what he would do if he had flashes and floaters in his vision. Video includes a discussion of retinal detachment.

Flashes and Floaters

The vitreous is the optically clear jelly that sits in the eye. On the front part of it is the lens, and on the back side is the retina. The retina is the very thin film that lines the back of the eye and sends electrical impulses back to the brain through the optic nerve.

The significance of floaters is that sometimes, as we tend to get older, the jelly shifts forward. This is an event called a posterior vitreous detachment. While that in itself isn't particularly concerning, in about 14% of people there is an associated retinal tear. A retinal tear is a big problem, because if fluid gets in under the retina through the hole caused by the tear, it can cause a retinal detachment - a potentially blinding situation.

What if I see flashes of light?

A number of people who have a posterior vitreous detachment also have flashing lights. The importance of this is that when the jelly shifts from the back of the eye, it can cause a little bit of tugging of the retina. The retina interprets that little tugging as a flash of light. Anytime someone notices both flashing lights and floaters, we're very concerned that the patient may have a retinal tear or a retinal detachment.

Are all flashing lights of retinal origin?

Another common cause of flashing lights is migraine headache. Unlike flashing lights that are associated with a retinal tear or retinal detachment, the flashing lights that are seen with migraine tend to last quite a lot longer (between 5 and twenty minutes), tend to be binocular in nature, and sometimes are associated with colours as well. With migraine headache, the flashing lights are followed by a fairly significant headache, nausea, vomiting, and sensitivity to light.

What should I expect on examination?

The key thing is that any one with new onset of floaters or flashes of light have to take this problem very seriously because in 14% of people, it could be a retinal tear which can lead to a retinal detachment. What I would expect is that someone who is very qualified to do both a thorough history and physical examination, which should include a visual acuity assessment to identify how well you can see, also a visual field assessment, because with a retinal detachment you can lose significant parts of your visual field. Then I would want the doctor to do a dilated examination, consisting of putting dilating drops in the eye so that the pupil gets big, allowing them to have a very good look insider the eye.

First, they will look at the vitreous (or the jelly portion of the eye), where they will be looking for any associated hemorrhage or tobacco dust. This signifies either a break of one of the blood vessels or tiny cells from the very back of the eye getting into the jelly. Both of these are very worrisome and we need to rule out a retinal tear or a detachment.

They will then do an indirect ophalmoscopy examination with a head-mounted ophthalmoscope. This allows the doctor to look at the back of the eye, sometimes also pushing on the back of the eye, in order to examine the peripheral part of the retina, as this is where the retinal tears are typically located.

Are there any tests that might be ordered?

Sometimes there will be so much blood in the jelly that we cannot see the retina. It is very important for us to assess whether it is a retinal detachment or not because that is really an emergent problem. In this situation we will do an ultrasound test to see whether the retina is flat, or if it is detached.

What are the treatment options?

Posterior vitrial detachment, where you see new floaters or new flashes of light, doesn't necessarily need to be treated: it can be an annoying situation, but with time the floaters are not going to be too much of a problem. If we notice a retinal tear, this is an emergent problem and what we typically do is use laser surgery to spot weld all the way around the retinal hole to prevent fluid from getting in under the retina.

If there is fluid already under the retina, we can do a number of things. We can inject gas into the eye which then pushes the retina up against the back and flattens it down. We still have to use laser to tack down the retina right around the hole to prevent fluid from seeping under it.

Another way to attack this problem is to operate on the outside part of the eye. We sew on a little silicone band and push the sclera (the white part of the eye) right right up against the retina and, again, use laser to tack down the area surrounding the hole.

Sometimes, if there is too much blood, or if there is a lot of traction on the retina, we actually have to cut into the eye and do what is called a vitrectomy. We clean out the blood inside the eye, and then operating on the inside of the eye we flatten down the retina.

If I had new onset of floaters and flashes….

If I had a new onset of floaters or flashes of light, I would take this problem very seriously. I would see someone on an emergent basis to make sure that I don't have a retinal tear or retinal detachment because we know that in about 14% of people these conditions are associated with it. The most likely scenario is just a shift of the jelly inside the eye which is not that concerning, but we still have to rule out those potential problems.